The objective of this study is to validate dynamic PET imaging of 18FDG uptake in muscle for measurement of glucose transport and phosphorylation. Once the technique is validated it will be used to assess glucose transport in the insulin resistance associated with NIDDM and obesity. Results from PET studies will be related to immunohistochemical studies in which Glut 4 is labelled and identified by quantitative confocal laser microscopy imaging of vastus lateralis muscle obtained by percutaneous biopsy. Combining these novel approaches will permit evaluation of the hypothesis that insulin-stimulated Glut 4 translocation within skeletal muscle will alter glucose utilization in NIDDM and obesity.